Abstract Atrial fibrillation (AF) is the most common arrhythmia encountered in clinical practice, affecting a growing population of over 2.2 million Americans. Paroxysmal atrial fibrillation (PAF) is a self-terminating form of the cardiac arrhythmia that comprises between 25% and 60% of AF cases. It is a growing epidemic in cardiovascular disease, predicted to afflict over 16 million people in the United States alone by 2050. Advancing age is a major risk factor for the development of atrial fibrillation. The prevalence of AF in people over the age of 75 is 6-8%, and it exceeds 15% in individuals over 80. For this reason, opportunistic screening of AF has been recommended in high risk individuals, including people over the age of 75, individuals over 65 with hypertension, and patients with previous stroke of uncertain etiology. PAF may be a single episode or clusters of abnormal rhythms with variable duration. PAF is often asymptomatic, and in those patients with symptoms, it has been estimated that for every symptomatic episode there are 10 asymptomatic ones. The self-terminating nature of PAF leads to its frequent under-diagnosis and consequent lack of use of established stroke prevention therapies. The proposed wearable screening tool based upon photoplethysmography ties clinical data collected at home directly to the clinician; is completely unobtrusive and does not require surgical implantation. This system could identify even brief episodes of atrial fibrillation and prevent significant morbidity and mortality by identifying individuals who would benefit from therapy, such as anticoagulation, that significantly reduces stroke risk. The innovation of this project is a low cost and practical solution for providing such screening. A prototype system will be developed and evaluated human pilot study in phase 1.